In nuclear the saying "there's always enough time to do it right the first time" comes to mind. Preventing rework and reducing risk to the safety of the public.
When it comes to the doe there are likely departments that could be trimmed back and interpretations of some laws to the cfr made a little more clear, but since the doe is in charge of everything nuclear it might be good to do a more indepth look at each department instead of a quick and careless wipe.
Currently nuclear power is regulated in a way of "bring me a rock and I'll tell you if it's the right rock, but if it isn't the right rock it will be painful.
I would say it depends on the content of the conference.
I'm a EE but work on process controls systems.
If it's a specialized industry specific users group where people in the same type of role swap operating experience, that's worth it. I.e. a heavily regulated industry where the safety of the public is involved like nuclear power, air planes, oil, etc.
The other type of conference is if your plant is specifically on a certain vendor for your core process.
So automation firms for industrial controls conferences fit this bill
If you're a Honeywell shop, go-to Honeywell users group, Allen Bradley go to process solutions users group, or anything with aveva going to aveva world.
If the production of your plant is dependent on the lifecycle of a vendor for parts, support and licenses, this type of conference is a must.
For both of these types there is a smart option to save a ton, volunteer to present. Most of the time if you present something worthwhile at a conference they waive the fee.